: :
: : In your first example, it is acceptable to use either version and I don't think one is more widely used that the other.

: : In the second example, to 'dance off' means that the sunlight moves about (probably because the trees are moving in the wind) illuminating one part of the trees then another, as if it were dancing.

:
: The conversation took place when 2 men were trying to fix a date for an event in the future.

Thanks Sphinx. The context doesn't change the answer for number one. Either is acceptable.